Is nanotechnology safe in the workplace?

As an increasing number of products which use nanotechnology begin appearing on the market, how can we ensure the workers who make them are protected from the possible risks of working with such minuscule materials?

Unlike traditional chemical engineering industries where workers' exposure to chemicals is regulated, it is still not clear whether protective masks, filters, and ventilation systems are sufficient to prevent harmful exposure to the latest nanosized substances. Photograph: Alamy

If the ideas of nanoscale science are going to be successfully integrated into our world, companies will need to make products that incorporate them. We talk often about the potential safety risks of those products to the consumers who buy them; but what about the people who make these things in the first place?

Factory workers, engineers and scientists working on cutting-edge products could be exposed to higher levels of nanosized particles (titanium dioxide if they are making sunscreens, say) or carbon nanotubes than any of the consumers who end up buying them. And, unlike traditional chemical engineering industries where workers' exposure to chemicals is regulated, it is still not clear whether protective masks, filters, and ventilation systems are sufficient to prevent harmful exposure to the latest nanosized substances.

There are a host of regulations in place to safeguard workers from the effects of harmful chemicals, but all too often nanoparticles slip through. The recent introduction of the European Union's Reach (registration, evaluation, authorisation and restriction of chemicals) legislation, for example, was set up to govern the production, use and import of chemicals in the continent, yet it fails to recognise the unique set of risks posed by nanoparticles. "Reach doesn't specifically discriminate between bulk form and nano form," says Mark Morrison, CEO of Institute of Nanotechnology, in Glasgow. Yet with nanoparticles, often the whole point of using them is to exploit the way that a material's properties or reactivity can change when its size is reduced. As such, a chemical that is innocuous in bulk form can be potentially harmful at the near-atomic scale.

A 2010 analysis by Prof Maria Giovanna Mattarolo, a professor of law at Padua University, Italy, showed that protection was far from adequate. "Scientific knowledge on the consequences of exposure and on the definition of tolerability doses still appears to be limited," she wrote. Despite the commitment of a number of European and international agencies there remains many unknown details about how nanoparticles interact with biological systems.

The traditional risk-assessment methodology required by EU directives cannot be adequately applied to the risks of nanoparticles, Mattarolo says, because they are defined by the real or potential risks of recognised or known materials. "The main question posed by nanotechnologies," she concludes, "is if the risk assessment and the safety and health measures as decided by the employers are really efficient. Can we generally assume that legal provisions are respected when facing new materials when clear toxicology data or binding legislative solutions are lacking?" As such no official guidelines on what constitutes an appropriate testing regimen yet exist, concludes her report.

In an attempt to address this oversight the European Parliament passed a resolution in December 2011 that nanoparticles must be covered by the current EU health and safety rules as part of a mid-term review of the EU's 2007-2012 health and safety at work strategy, which is due to end this year. Ultimately this should include a review of maximal limits of exposure for toxic substances, including nanomaterials, says Karima Delli, the French MEP with the Green Party who drafted the rules. That in turn, she suggests, should force employers, management and workers themselves to adapt the work environment in order to make it safer.

But Gabriel Aeppli, co-director of the London Centre for Nanotechnology at the University College London, is sceptical about the resolution. "It's pretty vague," he says. The draft only mentions nanomaterials once, and Aeppli questions the need for such resolutions when there are already Health and Safety Executive (HSE) guidelines and codes of conduct in place.

In any case, such risks can be largely mitigated through best practice, specifically by ensuring nanotubes, for example, are kept in a liquid solution form to minimise the risk of inhalation. The UK Control of Substances Hazardous to Health Regulations (2002) has been amended to include a list of requirements pertaining to the correct use of air filters and ventilations systems when handling nanotubes. "It's not terribly different from what we face with viruses and biohazards, where very small amounts of pathogens can have large effects," says Aeppli. "There is a risk but I don't believe you need to do any more than bring practice in line with what we do with biohazards."

But to take such a precautionary approach to all nanoparticles would be a rather broad brush stroke, says Morrison. "Not all nanomaterials are going to be [harmful] like that," he says. To treat all nanoparticles with the same caution would not only be unnecessary but it could be prohibitive to the industry. And in contrast, while there are indeed measures in place to protect workers from harmful exposure there is no guarantee that existing filter systems, protective clothing and knowledge about the dynamics of materials in the air are applicable to all nanomaterials, he says.

What is needed is a comprehensive means of assessing these nanomaterials. And that's exactly what is now underway: launched in November, NanoValid is a four-year project involving 29 partners from across the globe, representing academia, research institutes, governments and industry, which aims to establish reliable test methods to assess the exposure risk posed by materials at the nanoscale. This will be the first international effort to establish a set of reference methods for these materials, Morrison says. Only then, perhaps, can we start to eliminate the questions marks hanging over nanotechnology in the workplace.